Kobani Hit by Fresh Round of Islamic State Assaults

U.S.-Led Coalition Targets Militants’ Infrastructure With Airstrikes

BEIRUT—Fresh clashes shook the Syrian city of Kobani on Sunday as Islamic State militants fired mortar shells at Kurdish militia, and the U.S. and its Gulf allies launched airstrikes on the group’s fighters and oil infrastructure.

Islamic State fired at least four mortar shells at Kobani on Sunday, adding to more than 40 launched in the past few days, according to the Syrian Observatory for Human Rights, a monitoring group. The Islamists also detonated two car bombs near the center of the city—which lies on the Turkish border—on...